The parameter C_LOCKSTEP_SLAVE is set to one on all slave
MicroBlaze cores in the system, except the master (or primary)
core. The master core drives all the output signals, and handles the debug
functionality. The port Lockstep_Master_Out on the master is connected
to the port Lockstep_Slave_In on the slaves, to handle debugging. The
parameter C_TEMPORAL_DEPTH is provided to support debugging with
temporal lockstep, where the slave core execution is delayed a defined number of clock
cycles.
The slave cores should not drive any output signals, only receive input signals. This must be ensured by only connecting signals to the input ports of the slaves. For buses this either means that monitor interfaces must be used, or that each individual input port must be explicitly connected.
The port Lockstep_Out on the master and slave cores provide
all output signals for comparison. Unless an error occurs, individual signals from each
of the cores are identical every clock cycle.
To ensure that lockstep operation works properly, all input signals to the
cores must be synchronous. Input signals that could require external synchronization are
Interrupt, Reset, Ext_Brk, and
Ext_Nm_Brk.